Guideline for Batter Surface Stabilisation using vegetation

1 Guideline for Batter Surface Stabilisation using vegetation 2 About this release Title Guideline for Batter Surface Stabilisation using vegetation Approval and authorisation Name Prepared By A/Environment Manager Performance Improvement Scott Machar Environment Manager Performance Improvement Sean Hardiman Landscape Advisor Leigh Trevitt Approved By Principal Manager Environment Operations David Featherston Version Date Revision Description April 2015 Publication of Guideline for Batter Surface Stabilisation using vegetation Acknowledgements This publication includes material prepared for the Roads and Maritime Services by LandLoch Pty Ltd.

2 3 Contents 1. Use and scope of this Guideline 4 Purpose 4 Scope 4 How to use this Guideline 4 2. Batter Surface Stabilisation Decision support table 6 3. Factors to consider 8 Slope 8 Slope gradient 9 Slope length 10 Level of erosion protection 11 Growing media 12 Types of growing media 12 Growing media quality 12 Soil and growing media testing 14 Soil amelioration 14 Types of soil ameliorants 14 Soil amelioration in-situ 15 Soil amelioration during soil stripping 15 Soil amelioration within a stockpile 16 Amelioration post-establishment 16 Bioregion 16 Access requirements 16 Duration 17 Visual amenity and ecological outcome 17 vegetation type 17 Establishment time until erosion

3 Protection 18 Cost 19 Preparation 19 Rate of vegetation establishment 21 Quality assurance and surveillance 21 Establishment and maintenance 24 4. Glossary 255. Contacts 266. References 267. Fact sheets: Batter Surface Stabilisation techniques 27 Fact Sheet 1: Drill / Broadcast seeding 28 Fact Sheet 2: Soil binder Bitumen emulsion 30 Fact Sheet 3: Soil binder Tackifiers 32 Fact Sheet 4: Mulch / Topsoil mixes 34 Fact Sheet 5: Hydroseeding 36 Fact Sheet 6: Straw mulching 38 Fact Sheet 7: Hydromulching Standard 40 Fact Sheet 8: Hydromulching Bonded fibre matrix 42 Fact Sheet 9: Hydromulching Hydrocompost 44 Fact Sheet 10: Erosion control blanket Organic fibre 46 Fact Sheet 11: Erosion control blanket Synthetic 48 Fact Sheet 12.

4 Cellular confinement systems 50 Fact Sheet 13: Compost blanket 52 Fact Sheet 14: Placed turf 54 Fact Sheet 15: turf reinforcement mats 56 4 Section 1 Use and scope of this Guideline The construction and maintenance of roads often results in long linear stretches of Batter adjacent to the road alignment that are exposed and at risk of erosion if left unstabilised. This document has been prepared to provide guidance for NSW Roads and Maritime Services staff and contractors on Batter Surface Stabilisation solutions using vegetation . Purpose The purpose of this Guideline is to provide guidance on the suitability of various Batter Surface Stabilisation techniques using vegetation for a range of site conditions.

5 The Guideline considers: Factors that should be used to select appropriate Batter Surface Stabilisation solutions The aspects of specific Batter Surface Stabilisation techniques Existing Roads and Maritime specifications, procedures and guidelines Application for both temporary vegetation cover and long-term landscaping requirements The ability to use both temporary and long-term methods to achieve stability. Scope The Guideline addresses common Batter Surface Stabilisation scenarios using vegetation that are likely to be encountered by Roads and Maritime staff and contractors during the construction and maintenance of roads in NSW regardless of their scale or extent of works.

6 It includes sufficient detail on a range of Batter Surface Stabilisation techniques to allow users of this Guideline to make informed decisions on which techniques are most appropriate for their given site. Users of this Guideline must consider the whole of life maintenance costs and safety in design, construction and maintenance activities. The Guideline does not address geotechnical or civil engineering aspects of Batter Surface Stabilisation and a separate assessment of geotechnical stability should always be conducted. The techniques described in the Guideline can be used to aid geotechnical stability. It is important to note that the Guideline is for Surface Stabilisation .

7 All references to Stabilisation should be read as Surface Stabilisation . Whenever there is doubt about the geotechnical stability of a Batter contact your local Environment Officer for further advice on other disciplines and expertise to be sought (see Section 5 Contacts). How to use this Guideline Readers are encouraged to use the digital version of this Guideline as hyperlinks are provided throughout to allow easy navigation between sections they are indicated with blue underline. The Guideline provides background information in Sections 2-6, and then uses that background information to detail a range of specific Batter Surface Stabilisation techniques in Section 7 Fact sheets.

8 Section 1 Use and scope of this Guideline Section 2 Decision support table Section 3 Factors to consider Section 4 Glossary Section 5 Contacts for further information and expert advice Section 6 References Section 7 Fact sheets The limiting factor in most Batter Surface Stabilisation scenarios is the Batter slope. Section 2 provides a Decision support table that can be used to shortlist the Batter Surface Stabilisation techniques that might be suitable for a given site, based on the slope of the Batter /s in question. It also provides indicative information on the cost of each technique and the likely timeframe until erosion protection is achieved for each.

9 Once the slope of a Batter has been used to shortlist potentially suitable Batter Surface Stabilisation techniques, there are many other factors that must be considered in order to select the most appropriate Batter Surface Stabilisation technique for a given site. Information on other Factors to consider is provided in Section 3. Section 7 provides a series of fact sheets on the range of Batter Surface Stabilisation Techniques that are available, including detailed information on the Factors to consider as they relate to each technique. The process for using this Guideline is shown in Figure , over page. 5 Figure : Process for using this Guideline Identify slope gradient of subject site, and other site specific factors Consult Table Common Slope Descriptors Is my slope gradient covered in the Table Ye s My slope is between 4h:1v and 1h:2v No My slope is less than 4h:1v vegetation can be used successfully for slope Stabilisation .

10 The type of vegetation cover required is affected by the Factors to consider Refer to Section 3: Factors to consider and Section 7 Fact sheets for further advice Design Batter Surface Stabilisation technique that is suitable for the site No My slope is steeper than 1h:2v While vegetation may be used with many constraints, the main slope Surface Stabilisation will rely on a mix of vegatative and non-vegetative methods Can my slope be redesigned to include vegetation for Stabilisation ? No Seek advice from Regional Environment staff and Centre For Urban Design for Surface treatments and visual mitigation. See Section 5: Contacts Ye s Reassess Stabilisation treatments based on redesign 6 Section 2 Batter Surface Stabilisation Decision support table Table 2 Decision support table provides a summary of the slope conditions for each Batter Surface Stabilisation technique that might be suitable, as well as the indicative cost of each to install and the time period until each technique will provide Surface erosion protection (see Key below).